1. Field of the Invention
The invention relates to a building board, in particular a flooring panel, with a core comprising at least one upper layer and one lower layer of wood fibers or wood chips glued with an adhesive and pressed to one another, which is provided on at least its top side with a pattern that is covered with a sealing layer in which a structure corresponding to the pattern is embossed.
2. Discussion of Background Information
A building board of this type is known, e.g., from DE 102 52 863. Building boards with a core of wood material have been commercially available for many years as laminate panels as a substitute for parquet flooring. In addition to mechanical and hygroscopic requirements, flooring panels must also meet high demands in terms of visual impression and feel. The main task in this respect is to create the impression of a natural material, e.g., wood or stone. However, fantasy patterns are also used.
Generic flooring panels therefore not only have a decorative layer, which can be embodied as a separate printed paper ply or printed directly onto the core of the panel, but also have a relief embossed into the surface. This surface structure can be embodied in a flat or fine manner, wherein both structures can overlap. With high-quality products, they are exactly matched to the pattern beneath. One skilled in the art refers to this as a pattern-synchronous surface structure.
DE 102 20 501 discloses a directly laminated board, in which a dry paper without resin impregnation is used as decorative paper and has a great absorption capacity for the resin of the adhesive layer, with which the decorative paper is attached to the core. At deeply embossed points of the cover layer the decorative paper can dip into the adhesive layer without being squashed against a hard surface of the core. A gentle processing of the decorative paper is to be possible during the hot pressing in this manner.
The disadvantage is that surface structures of this type are limited in their depth. Conventionally, they have a depth of approx. 100 μm. Deeper structures can be achieved, if at all, only with increased compacting forces and long pressing times. Greater compacting forces require complex presses and reinforced tools. Long press times have a negative impact on the mechanical properties of the support board of wood material.
AT 367 137 discloses a weather-resistant board of wood-fiber materials that is characterized in that it comprises on the one hand the support material composed of lignocellulose-containing fibers and/or chips effecting the shaping and dimensional stability and/or organic materials, binders and additives otherwise treated, and on the other hand a firmly adhering outer layer from the group of weather-resistant vulcanizable elastomers, which are firmly connected to one another without additional connection of the medium chiefly through reciprocal mechanical anchoring in the marginal zones facing one another of carrier substance and outer coating.